100 Octane LL AV Gas

[L16pilot]

Originally Posted by turbo69bird

There’s a few things I don’t agree with in that article . One is it’s not formulated for low RPM that’s relative. Most lycoming engines run at WOT at 2700 ROM or less many 2100 ROMs on the take off roll. So what low RPM he’s taking about and what the High Rpm?

If it doesn’t last longer that’s news to the aviation and landscapers who use it specifically because it doesn’t gel up like regular fuels.
Also airplane engines have 7.0 to 7.9 to one compression in its most popular engines
MOR rating is only half the story as well when it comes to octane .
I’ve personally drained fuel from an airplane wing that sat for over 10 years that didn’t have a tinge of varnish smell or flakes to it.

Regarding the author's comment about 100LL not being formulated for low RPM, I think what needs to be considered is that when 100LL was created, Tetraethyl lead was the best option to increase the octane rating based on the technology available while meeting all other requirements of recip aviation engines. Your comment about typical GA aircraft engines is correct, (2700 rpm or less), but I think the other performance factors outweighed the operating RPM range during development.

Also, for me personally, Avgas provides other valuable advantages with the prime one being it does not "go bad" in engines/carburetors/fuel systems that sit for extended periods of time saving tons of time/money/effort/frustration. I for one am looking forward to mass distribution and availability of the new GAMI G100UL fuel which promises all the performance/characteristics of 100LL, but without the tetraethyl lead.

[turbo69bird]

Originally Posted by L16pilot

Regarding the author's comment about 100LL not being formulated for low RPM, I think what needs to be considered is that when 100LL was created, Tetraethyl lead was the best option to increase the octane rating based on the technology available while meeting all other requirements of recip aviation engines. Your comment about typical GA aircraft engines is correct, (2700 rpm or less), but I think the other performance factors outweighed the operating RPM range during development.

Also, for me personally, Avgas provides other valuable advantages with the prime one being it does not "go bad" in engines/carburetors/fuel systems that sit for extended periods of time saving tons of time/money/effort/frustration. I for one am looking forward to mass distribution and availability of the new GAMI G100UL fuel which promises all the performance/characteristics of 100LL, but without the tetraethyl lead.

I agree with those point but previous author said that the 100ll didn’t have a longer shelf life.

Idk if I’m thrilled w the new fuel coming online personally promises promises, heard it before we heard that with ethanol being added to fuel it wouldn’t be any differnt then our fuel lines started disintegrating . That’s bad enough in my boat or my car but I don’t like to mess around w any changes in my airplane . It took some time to see the effects of ethanol too it wasn’t right away . I won’t be flying my kids for a while when the new fuel comes out that is all I know .

[L16pilot]

Originally Posted by turbo69bird

I agree with those point but previous author said that the 100ll didn’t have a longer shelf life.

Idk if I’m thrilled w the new fuel coming online personally promises promises, heard it before we heard that with ethanol being added to fuel it wouldn’t be any differnt then our fuel lines started disintegrating . That’s bad enough in my boat or my car but I don’t like to mess around w any changes in my airplane . It took some time to see the effects of ethanol too it wasn’t right away . I won’t be flying my kids for a while when the new fuel comes out that is all I know .

I agree with the shelf life issue as well. As for race gas, I have experience with VP, cannot recall exactly which formula, but it did show signs of going bad in an un-opened 5 gallon can within a couple of years...an experience I've never had with 100LL.

As for the new G100UL, all we have to go by is the extensive testing performed by GAMI which far exceeded the FAA's requirements. True, time will tell, but all indications are positive with no ill effects. Whether we like it or not, 100LL is on the EPA's radar as the single largest source of lead emissions into the atmosphere and once approved unleaded aviation gasoline becomes readily available, the EPA will move quick to ban 100LL.

Also, the video link you posted is excellent...never knew the history behind tetraethyl lead and CFCs....thanks!